U.S. patent application number 11/110835 was filed with the patent office on 2005-10-27 for image display device for rotating an image displayed on a display screen.
This patent application is currently assigned to NEC Viewtechnology, Ltd.. Invention is credited to Nishida, Michiya.
Application Number | 20050237346 11/110835 |
Document ID | / |
Family ID | 35135950 |
Filed Date | 2005-10-27 |
United States Patent
Application |
20050237346 |
Kind Code |
A1 |
Nishida, Michiya |
October 27, 2005 |
Image display device for rotating an image displayed on a display
screen
Abstract
An image display device comprises a frame arranged along the
periphery of display screen anda plurality of detectors mounted on
the frame, each for generating a detection signal in response to an
object positioned outside of the frame. Each of detectors generates
a detection signal indicative of the distance to an object that is
present in a direction associated therewith. A control circuit
selects a detection signal indicative of the shortest distance of
the detection signals. The control circuit controls the direction
of an image that is displayed on a display screen such that the
bottom of the image is moved to a side corresponding to the
detector that generates the selected detection signal.
Inventors: |
Nishida, Michiya; (Tokyo,
JP) |
Correspondence
Address: |
MCGINN & GIBB, PLLC
8321 OLD COURTHOUSE ROAD
SUITE 200
VIENNA
VA
22182-3817
US
|
Assignee: |
NEC Viewtechnology, Ltd.
Tokyo
JP
|
Family ID: |
35135950 |
Appl. No.: |
11/110835 |
Filed: |
April 21, 2005 |
Current U.S.
Class: |
345/697 |
Current CPC
Class: |
G09G 5/00 20130101; G09G
2340/0492 20130101 |
Class at
Publication: |
345/697 |
International
Class: |
H04N 005/50 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 22, 2004 |
JP |
2004-126838 |
Claims
What is claimed is:
1. An image display device comprising: a display unit having a
display screen for displaying an image; a frame arranged along a
periphery of said display screen; a plurality of detectors mounted
on said frame, each for generating a detection signal in response
to an object positioned outside of said frame; and a controller for
controlling an image displayed on said display screen based on the
detection signals generated from said respective detectors.
2. The image display device according to claim 1, wherein: said
display screen is in a rectangular shape, and said plurality of
detectors comprise four detectors each mounted at a location on
said frame close to each of four sides of said display screen.
3. The image display device according to claim 1, wherein: said
display screen is in a rectangular shape, and said plurality of
detectors comprise three detectors each mounted at a location on
said frame close to each of three sides of said display screen.
4. The image display device according to claim 1, wherein: said
display screen is in a rectangular shape, and said plurality of
detectors comprise two detectors each mounted at a location on said
frame close to each of two sides of said display screen.
5. The image display device according to claim 1, wherein said
controller detects a side to which the user is close from sides
which define said display screen based on the detection signals
generated from said plurality of detectors, and controls the
direction of the image such that a bottom of the image is moved to
the detected side.
6. The image display device according to claim 1, wherein each of
said detectors is a radiant heat sensor for detecting an amount of
heat radiated from an object in order to generate a signal
indicative of the detected amount of radiant heat as the detection
signal.
7. The image display device according to claim 1, wherein each of
said detectors is a distance sensor.
8. The image display device according to claim 1, further
comprising an image signal input unit for receiving an image signal
supplied from an external device through a wire, wherein said
controller converts the image signal based on the detection signals
generated from said respective detectors in order to control a
direction of an image represented by the image signal on said
display screen, and displays an image represented by the converted
image signal on said display screen.
9. The image display device according to claim 8, further
comprising storing means for preserving the image signal received
by said image signal input unit.
10. The image display device according to claim 9, wherein said
storing means is removable.
11. The image display device according to claim 1, further
comprising a generator for generating an image signal
representative of the image, wherein said controller converts the
image signal generated by said generator based on the detection
signals generated from said respective detectors in order to
control a direction of an image represented by the image signal
generated by said generator on said display screen, and displays an
image represented by the converted image signal on said display
screen.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an image display device,
and more particularly, to an image display device that can change
the direction of an image, for example, rotate the image displayed
on a display screen.
[0003] 2. Description of the Related Art
[0004] Conventionally, a certain image display device is known to
control the direction of an image displayed on its display screen
such that the bottom of the displayed image is positioned at a
vertically lower position of the display screen even if the display
screen is rotated.
[0005] JP-2003-60940-A and JP-2003-274366-A each describe an
electronic camera for controlling the direction of an image
displayed on a display screen.
[0006] The electronic camera detects the posture of the electronic
camera by a camera posture detector. The electronic camera records
the detected posture together with an image captured by the
electronic camera. Upon reproduction of the recorded image on a
display screen, the electronic camera controls the direction of the
image displayed on the display screen based on the detected posture
that is recorded together with the image. A gravity sensor is used
as the camera posture detector (see JP-2003-274366-A).
[0007] JP-H9-37187-A describes an image display device that rotates
an image displayed on its display screen.
[0008] This image display device detects the posture of a user who
is watching an image displayed on the image display device, instead
of the posture of the image display device itself, by an infrared
sensor. The image display device rotates the image displayed on the
display screen by 90.degree. when the user is sprawling. The
infrared sensor senses a region in front of the display screen.
[0009] Japanese Patent No. 3013808 describes techniques for scaling
up and down an image represented by an image signal.
[0010] When a gravity sensor detects the posture of an image
display device as described in JP-2003-60940-A and
JP-2003-274366-A, the following problems can arise.
[0011] When an image display device is installed such that its
display screen is substantially horizontal to the ground surface,
the result that is detected by the gravity sensor doesn't indicate
the position of the user who is viewing the display screen.
Therefore, the gravity sensor cannot always correctly detect the
position of the user who is viewing the display screen.
Accordingly, when the image display device is installed such that
the display screen is substantially horizontal to the ground
surface, the image display device cannot rotate a displayed image
so that the user can easily watch the displayed image.
[0012] In addition, the gravity sensor cannot detect the posture of
the image display device in a weightless environment such as a
space station.
[0013] The image display device described in JP-H9-37187-A can
arise the following problems, because the infrared sensor that is
included in the image display device has a detectable region in
front of the display screen.
[0014] When the image display device is installed such that the
display screen is substantially horizontal to the ground surface,
and when the user is watching an image displayed thereon at a
position out of the front of the displayed image, the infrared
sensor cannot always correctly detect the position of the user who
is watching the displayed image.
[0015] FIG. 1 is an explanatory diagram illustrating an exemplary
situation in which image display device 101 is installed such that
display screen 102 of image display device 101 is substantially
horizontal to the ground surface, and when user 201 is viewing
display screen 102 at a position out of the front of display screen
102 (specifically at a position beside display screen 102).
[0016] Infrared sensor 103 has a detectable region in front of
display screen 102. Therefore, in the state illustrated in FIG. 1,
infrared sensor 103 cannot detect user 201. Consequently, image
display device 101 cannot control the direction of an image such
that the user 201 can easily watch the displayed image.
SUMMARY OF THE INVENTION
[0017] It is an object of the present invention to provide an image
display device that is capable of adjusting the direction of an
image that is displayed on a display screen such that the user can
easily watch the displayed image even if the image display device
is installed such that the display screen is substantially
horizontal to the ground surface.
[0018] To achieve the object, an image display device includes a
display unit having a display screen for displaying an image, a
frame arranged along the periphery of the display screen, a
plurality of detectors mounted on the frame, each for generating a
detection signal in accordance with an object positioned outside of
the frame, and a controller for controlling an image displayed on
the display screen based on the detection signals generated from
the respective detectors.
[0019] According to the image display device described above, an
image displayed on the display screen is controlled based on the
detection signals generated from the respective detectors. Each
detector generates a detection signal in response to an object that
is positioned outside the frame. Therefore, each detector can
detect an object that exists beside the display screen.
Consequently, the image, which is displayed on the display screen,
is changed based on the result of detecting the object that exists
beside the display screen.
[0020] Thus, the image display device can automatically display on
the display screen an image that the user can easily watch, even
when the image display device is installed such that the display
screen is substantially horizontal to the ground surface.
[0021] Preferably, the display screen is in a rectangular shape,
and the plurality of detectors include four detectors each mounted
at a location on the frame close to each of four sides of the
display screen.
[0022] According to the image display device described above, an
image displayed on the display screen can be controlled based on
the result of comparing the detection signals generated from the
four detectors.
[0023] Also preferably, the display screen is in a rectangular
shape, and the plurality of detectors include three detectors each
mounted at a location on the frame close to each of three sides of
the display screen.
[0024] According to the image display device described above, the
configuration can be simplified as compared with the image display
device that employs four detectors.
[0025] Further preferably, the display screen is in a rectangular
shape, and the plurality of detectors comprise two detectors each
mounted at a location on the frame close to any of two sides of the
display screen.
[0026] According to the image display device described above, the
configuration can be further simplified as compared with the image
display device that employs three detectors.
[0027] Preferably, the controller detects a side, to which the user
is close, from sides that define the display screen based on the
detection signals that are generated from the plurality of
detectors, and controls the direction of the image such that the
bottom of the image is moved to the detected side.
[0028] According to the image display device described above, the
image display device can automatically display on the display
screen an image that the user can easily watch, even if the image
display device is installed such that the display screen is moved
in whichever direction.
[0029] Each of the detectors is preferably a radiant heat sensor
for detecting the amount of heat radiated from an object in order
to generate a signal, which indicates the detected amount of
radiant heat, as the detection signal.
[0030] Alternatively, each of the detectors is preferably a
distance sensor.
[0031] Preferably, the image display device further includes an
image signal input unit for receiving an image signal that is
supplied from an external device through a wire, wherein the
controller converts the image signal based on the detection signals
generated from the respective detectors in order to control the
direction of an image, which is represented by the received image
signal, on the display screen, and displays an image represented by
the converted image signal on the display screen.
[0032] Also preferably, the image display device further includes
storing means for preserving an image signal received by the image
signal input unit.
[0033] The image display device is preferably configured such that
the storing means is removable.
[0034] Preferably, the image display device further includes a
generator for generating an image signal that represents the image,
wherein the controller converts the image signal generated by the
generator based on the detection signals generated from the
respective detectors in order to control the direction of an image,
which is represented by the generated image signal, on the display
screen, and displays an image represented by the converted image
signal on the display screen.
[0035] According to the present invention, the image display device
can detect an object that exists beside the display screen, and
change the direction of an image displayed on the display screen
based on the result of the detection. Therefore, even if the image
display device is installed, for example, such that the display
screen is substantially horizontal to the ground surface, the image
display device can automatically display on the display screen an
image that the user can easily watch.
[0036] The above and other objects, features, and advantages of the
present invention will become apparent from the following
description with reference to the accompanying drawings which
illustrate examples of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0037] FIG. 1 is a plan view illustrating a conventional image
display device;
[0038] FIG. 2 is a plan view illustrating an image display device
according to one embodiment of the present invention;
[0039] FIG. 3 is a block diagram illustrating the image display
device according to the embodiment of the present invention;
[0040] FIG. 4 is a plan view illustrating the image display device
according to the embodiment of the present invention; and
[0041] FIG. 5 is a plan view illustrating an image display device
according to another embodiment of the present invention.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0042] FIG. 2 is a plan view illustrating from above a situation in
which image display device 1 is installed on a desk (not shown),
and user 2 is watching an image displayed on image display device
1.
[0043] In FIG. 2, image display device 1 comprises display screen
11, frame 12, and detectors 13-16.
[0044] Image display device 1 is preferably a highly portable thin
image display device which utilizes a flat panel, for example, a
liquid crystal display (LCD), a plasma display (PDP) or the like.
Highly portable thin image display devices are used for display
devices of notebook type personal computers or display devices of
electronic books. A variety of manners can be expected in the
utilization of the highly portable thin image display devices. For
example, as illustrated in FIG. 2, a highly portable thin image
display device may be installed on a desk so that its display
screen is substantially in parallel with the ground surface.
[0045] Image display device 1 is not limited to such a highly
portable thin image display device utilizing a flat panel.
[0046] Display screen 11 is defined by sides 11a, 11b, 11c and 11d.
Side 11a is an example of a first side. Side 11b is an example of a
second side. Side 11c is an example of a third side. Side 11d is an
example of a fourth side. Display screen 11 displays an image
represented by an image signal.
[0047] In this embodiment, display screen 11 is in a rectangular
shape. Specifically, sides 11a, 11c are parallel and equal in
length to each other, while sides 11b, 11d are parallel and equal
in length to each other, with an angle of 90.degree. formed by
sides 11a and 11b. The shape of display screen 11 is not limited to
a rectangle, but may be changed as appropriate.
[0048] Frame 12 is disposed around the periphery of display screen
11.
[0049] Detector 13 is an example of a first detector. Detector 13
may be, for example, a radiant heat sensor such as an infrared
sensor, or a distance sensor.
[0050] The distance sensor, which is used as detector 13, measures
the distance to an object, for example, based on a time period from
a time, which an ultrasonic wave is emitted from the sensor, to a
time, which a reflected wave of the ultrasonic wave returns
thereto. The distance sensor used as detector 13 is not limited to
a sensor utilizing ultrasonic waves, but may be changed as
appropriate. The distance sensor is only required to generate a
distance signal (first detection signal) that indicates the
distance to an object.
[0051] The radiant heat sensor, which is used as detector 13,
preferably has characteristics to generate a higher output voltage
that indicates the amount of radiant heat detected thereby when the
sensor detects a larger amount of radiant heat. In this event,
detector 13 generates a higher output voltage (first detection
signal) when a human, who is an object, is closer to detector
13.
[0052] Detector 13 is mounted in first portion 12a on frame 12 in
close proximity to side 11a. Detector 13 has a detectable region
outside of frame 12 around first portion 12a (for example, in a
direction indicated by arrow a shown in FIG. 2). Detector 13
generates a first detection signal in response to an object that
exists within its detectable region. Detector 13 is corresponded to
side 11a.
[0053] Sensor 14 is an example of a second sensor. Sensor 14 is,
for example, a radiant heat sensor such as an infrared sensor, or a
distance sensor.
[0054] The distance sensor, which is used as detector 14, measures
the distance to an object based on a time period from a time, which
an ultrasonic wave is emitted from the sensor, to a time, which a
reflected wave of the ultrasonic wave returns thereto. The distance
sensor used as detector 14 is not limited to a sensor utilizing
ultrasonic waves, but can be changed as appropriate. The distance
sensor is only required to generate a distance signal (second
detection signal) indicative of the distance to an object.
[0055] Also, the radiant heat sensor, which is used as detector 14,
preferably has characteristics to generate a higher output voltage
that indicates the amount of radiant heat detected thereby when the
sensor detects a larger amount of radiant heat. In this event,
detector 14 generates a higher output voltage (second detection
signal) when a human, who is an object, is closer to detector
14.
[0056] Detector 14 is mounted in second portion 12b on frame 12 in
close proximity to side 11b. Detector 14 has a detectable region
outside of frame 12 around second portion 12b (for example, in a
direction indicated by arrow b shown in FIG. 2). Detector 14
generates a second detection signal in response to an object that
exists within its detectable region. Detector 14 is corresponded to
side 11b.
[0057] Sensor 15 is an example of a third sensor. Sensor 15 is, for
example, a radiant heat sensor such as an infrared sensor, or a
distance sensor.
[0058] The distance sensor, which is used as detector 15, measures
the distance to an object based on a time period from a time, which
an ultrasonic wave is emitted from the sensor, to a time, which a
reflected wave of the ultrasonic wave returns thereto. The distance
sensor, which is used as detector 15 is not limited to a sensor
utilizing ultrasonic waves, but can be changed as appropriate. The
distance sensor is only required to generate a distance signal
(third detection signal) indicative of the distance to an
object.
[0059] Also, the radiant heat sensor, which is used as detector 15,
preferably has characteristics to generate a higher output voltage
that indicates the amount of radiant heat detected thereby when the
sensor detects a larger amount of radiant heat. In this event,
detector 15 generates a higher output voltage (third detection
signal) when a human, who is an object, is closer to detector
15.
[0060] Detector 15 is mounted in third portion 12c on frame 12 in
close proximity to side 11c. Detector 15 has a detectable region
outside of frame 12 around third portion 12c (for example, in a
direction indicated by arrow c shown in FIG. 2). Detector 15
generates a third detection signal in response to an object that
exists within its detectable region. Detector 15 is corresponded to
side 11c.
[0061] Sensor 16 is an example of a fourth sensor. Sensor 16 is,
for example, a radiant heat sensor such as an infrared sensor, or a
distance sensor.
[0062] The distance sensor, which is used as detector 16, measures
the distance to an object based on a time period from a time, which
an ultrasonic wave is emitted from the sensor, to a time, which a
reflected wave of the ultrasonic wave returns thereto. The distance
sensor, which is used as detector 16, is not limited to a sensor
utilizing ultrasonic waves, but can be changed as appropriate. The
distance sensor is only required to generate a distance signal
(fourth detection signal) that indicates the distance to an
object.
[0063] Also, the radiant heat sensor, which is used as detector 16,
preferably has characteristics to generate a higher output voltage
that indicates the amount of radiant heat detected thereby when the
sensor detects a larger amount of radiant heat. In this event,
detector 16 generates a higher output voltage (fourth detection
signal) when a human, who is an object, is closer to detector
16.
[0064] Detector 16 is mounted in fourth portion 12d on frame 12 in
close proximity to side 11d. Detector 16 has a detectable region
outside of frame 12 around fourth portion 12d (for example, in a
direction indicated by arrow d shown in FIG. 2). Detector 16
generates a fourth detection signal in response to an object that
exists within its detectable region. Detector 16 is corresponded to
side 11d.
[0065] Sensors 13, 14, 15, 16 are preferably of the same type.
[0066] In FIG. 3, components identical to those shown in FIG. 2 are
designated the same reference numerals.
[0067] In FIG. 3, image display device 1 comprises sensor 13-16,
image signal input unit 17, operation board 18, storage unit 19,
display unit 20, memory 21, and control circuit 22.
[0068] Image signal input unit 17 receives an image signal that
represents an image. For example, image signal input unit 17
includes an antenna (not shown). Image signal input unit 17
receives an image signal transmitted over the air from an external
radio transmitter through its antenna. Also, image signal input
unit 17 also includes an input terminal (not shown). When the input
terminal is connected to a cable that provides an image signal,
image signal input unit 17 receives an image signal that is
supplied from an external device such as a personal computer
through the cable.
[0069] Operation board 18 is operated by the user. Operation board
18 receives a variety of inputs indicated by the user's
operations.
[0070] Storage unit 19 includes a recording medium such as DVD
(Digital Versatile Disk). Storage unit 19 preserves image signals
received by image signal input unit 17. Storage unit 19 is
preferably removable from image display device 1.
[0071] Display unit 20 has display screen 11 shown in FIG. 2.
Display unit 20 displays on display screen 11 an image that is
represented by an image signal supplied from control circuit
22.
[0072] Memory 21 is a recording medium readable by a computer.
Memory 21 records a program for defining the operation of image
display device 1.
[0073] Controller 22 includes a CPU that is an example of computer.
Control circuit 22 reads the program recorded in memory 21. Control
circuit 22 executes the read program to perform a variety of
operations. For example, control circuit 22 generates an image
signal, which indicates an image, based on entries from the user
received by operation board 18, like a personal computer, an
electronic databook or the like. Control circuit 22 may store the
generated image signal in storage unit 19. Control circuit 22 may
also store an image signal received by image signal unit 17 in
storage unit 19. Control circuit 22 preferably stores an image
signal received by image signal input unit 17 in storage unit 19
when the user operates operation board 18 in order to enter a
storage command.
[0074] Control circuit 22 also receives the first detection signal
generated from detector 13; the second detection signal generated
from detector 14; the third detection signal generated from
detector 15; and the fourth detection signal generated from
detector 16. Control circuit 22 controls the direction of an image,
which is displayed on display screen 11 of display unit 20, based
the first, second, third, and fourth detection signals.
[0075] Specifically, control circuit 22 converts an image signal,
which is generated based on an entry from the user received by
operation board 18, based on the first, second, third, and fourth
detection signals such that an image, which is displayed on display
screen of display unit 20, is changed in direction.
[0076] Control circuit 22 also converts an image signal, which is
received by image signal input unit 17, based on the first, second,
third, and fourth signals such that an image displayed on display
screen 11 of display unit 20 is change in direction.
[0077] Control circuit 22 further converts an image signal, which
is preserved in storage unit 19, based on the first, second, third,
and fourth detection signal such that an image displayed on display
screen 11 of display unit 20 is changed in direction.
[0078] Control circuit 22 displays the image, which is represented
by the converted image signal, on display screen 11 of display unit
20.
[0079] Control circuit 22 selects a detection signal, which
satisfies predetermined conditions, from the first, second, third,
and fourth signals. For example, control circuit 22 selects a
detection signal that indicates the highest output voltage when
detectors 13-16 comprise radiant heat sensors. Alternatively,
control circuit 22 selects a detection signal that indicates the
shortest distance when detectors 13-16 comprise distance
sensors.
[0080] Controller 22 preferably controls the direction of the image
such that the bottom of the image is moved to a side corresponding
to a detector that has generated the selected detection signal.
[0081] Next, the operation will be described.
[0082] Control circuit 22 operates detectors 13, 14, 15 and 16 at
predetermined time intervals, for example, when image display
device 1 is powered on. Alternatively, control circuit 22 may
operate detectors 13, 14, 15 and 16 when the user operates
operation board 18 in order to enter a detection start command.
[0083] Detector 13, which has started the operation, supplies
control circuit 22 with a first detection signal in accordance with
an object that exists in its detectable region. Detector 14, which
has started the operation, supplies control circuit 22 with a
second detection signal in accordance with an object that exists in
its detection region. Detector 15, which has started the operation,
supplies control circuit 22 with a third detection signal in
accordance with an object that exists in its detectable region.
Detector 16, which has started the operation, supplies control
circuit 22 with a fourth detection signal in accordance with an
object that exists in its detection region.
[0084] Control circuit 22 compares the first, second, third, and
fourth detection signals with one another. Subsequently, control
circuit 22 selects a detection signal, which satisfies
predetermined conditions, from the first, second, third, and fourth
detection signal. For example, control circuit 22 selects a
detection signal that indicates the highest output voltage when
detectors 13-16 comprise radiant heat sensors. On the other hand,
control circuit 22 selects a detection signal that indicates the
shortest distance when detectors 13-16 comprise distance
sensors.
[0085] For example, in the state illustrated in FIG. 2, control
circuit 22 selects the third detection signal from the first,
second, third, and fourth detection signals. Control circuit 22
converts an image signal for display unit 20 such that the bottom
of an image is moved to a side corresponding to the detector that
has generated the selected detection signal.
[0086] The image signal for display unit 20 may be an image signal
received by image signal input unit 17, or an image signal stored
in storage unit 19, or an image signal generated by control circuit
22.
[0087] For example, in the state illustrated in FIG. 2, control
circuit 22 displays the image such that the bottom of the image is
moved to side 11c corresponding to detector 15 that has generated
the third detection signal.
[0088] In this embodiment, control circuit 22 scales up or down the
image represented by the image signal such that the overall image
(for example; the overall image having the area of one page), which
is represented by the image signal, is fitted in display screen 11
in a sufficient size.
[0089] For example, control circuit 22 scales up or down the image
represented by the image signal such that the size of the overall
image (for example, the overall image having the area of one page),
which is represented by the image signal, is the largest one of
images sizes which fit in display screen 11. Control circuit 22 may
employ, for example, the technique described in JP-9-37187-A when
it scales up or down an image signal.
[0090] In the state illustrated in FIG. 2, control circuit 22
compresses a rectangular document (image) with more height than
width such that the rectangular document with more height than
width fits in rectangular display screen 11 with more width than
height. Control circuit 22 displays the compressed document (image)
on display unit 20. For this reason, display screen 11 shown in
FIG. 2 includes margins 11e and 11f.
[0091] FIG. 4 is a plan view illustrating a situation in which user
2 recognizes that the image, which is viewed in the state
illustrated in FIG. 2, is a document in format with more height
than width (for example, a catalog or the like), so that user 2 has
rotated image display device 1 by 90 degrees in the
counter-clockwise direction. In FIG. 4, components identical to
those in FIG. 2 are designated the same reference numerals.
[0092] In the state illustrated in FIG. 4, when control circuit 22
operates detectors 13, 14, 15 and 16, detectors 13, 14, 15 and 16
supply control circuit 22 with a first, a second, a third, and a
fourth detection signal, respectively.
[0093] In the state illustrated in FIG. 4, control circuit 22
selects the second detection signal from the first, second, third,
and fourth detection signals. Then, control circuit 22 converts the
image signal for display unit 20 such that the bottom of the image
is moved to side 11b corresponding to detector 14 that has
generated the selected second detection signal. Consequently, the
image shown in FIG. 2 is rotated by 90 degrees in the clock-wise
direction to display an image shown in FIG. 4.
[0094] In the state illustrated in FIG. 4, because the image is
displayed in format with more height than width on display screen
11, the displayed image is larger than that shown in FIG. 2. Thus,
in the state illustrated in FIG. 4, the user can be provided with a
more visible image than that shown in FIG. 2.
[0095] When detectors 13-16 comprise distance sensors, the
following situation will arise.
[0096] When image display device 1 is installed on a stand or a
floor such that display screen 11 is substantially vertical to the
ground surface, the distance, which is indicated by a detection
signal generated by a sensor which detects the distance from image
display device 1 to the stand or floor, is shorter than the
distance indicated by the remaining detection signals.
[0097] For this reason, when image display device 1 is installed on
a stand or a floor such that display screen 11 is substantially
vertical to the ground surface, the bottom of an image is moved to
the bottom of display screen 11. Thus, image display device 1 can
provide an image that the user can easily watch.
[0098] According to this embodiment, image display device 1 can
detect a user who exists beside display screen 11. Then, the
direction of the image displayed on display screen 11 is controlled
based on the result of the detection. Thus, image display device 1
can automatically display on display screen 11 an image that the
user can easily watch even if image display device 1 is installed
such that display screen 11 is substantially horizontal to the
surface ground.
[0099] In this embodiment, control circuit 22 detects a side close
to the user from the sides that define display screen 11 based on
the first, second, third, and fourth detection signals. Control
circuit 22 controls the direction of an image on display screen 11
such that the bottom of the image is moved to the detected side. In
this way, image display device 1 can automatically display an image
that the user can easily watch, in other words, an image
corresponding to the direction in which the user is viewing.
[0100] This embodiment is particularly effective when image display
device 1 is a highly portable thin image display device that
utilizes a flat panel. This is because it is anticipated that the
highly portable thin image display device, for example, an image
display device utilizing a flat panel such as LCD or PDP is often
installed and used such that display screen 11 thereof is
substantially horizontal to the ground surface. According to this
embodiment, even if image display device 1 is used in such a way,
image display device 1 automatically displays on display screen 11
an image that the user can easily watch.
[0101] It should be understood that in the embodiment described
above, the illustrated configuration is a mere example, and the
present invention is not limited to that configuration.
[0102] For example, while in the foregoing embodiment, four
detectors are mounted on frame 12, the number of detectors mounted
on frame 12 is not limited to four but can be changed as
appropriate. For example, a plurality of detectors may be mounted
at locations in close proximity to one side of display screen 11.
Alternatively, three detectors may be mounted on frame 12, such
that control circuit 22 controls the direction of an image
displayed on display screen 11 based on detection signals of the
three detectors. For example, one of detectors 13, 14, 15, 16 may
be removed in the embodiment illustrated in FIG. 2. Control circuit
22 may control the direction of an image such that the bottom of
the image is moved to a side corresponding to a detector that has
detected a signal indicative of the shortest distance of the three
detection signals generated by the three detectors mounted on frame
12. Further, when all of three detection signals, which are
generated by the three detectors mounted on frame 12, indicate
distances equal to or longer than a predetermined distance, control
circuit 22 controls the direction of an image such that the bottom
of the image is moved to a side corresponding to the removed
detector.
[0103] In the foregoing alternative, the configuration can be
simplified because a less number of detectors can be used than in
the embodiment illustrated in FIG. 1.
[0104] Further alternatively, two detectors may be mounted on frame
12, and control circuit 22 may control the direction of an image
displayed on display screen 11 based on detection signals generated
by the two detectors.
[0105] FIG. 5 is a plan view illustrating an exemplary image
display device which has two detectors mounted on frame 12. In FIG.
5, components identical to those shown in FIG. 1 are designated the
same reference numerals.
[0106] In FIG. 5, detectors 14a and 16a are mounted on frame 12.
Detector 14a is mounted at a position on frame 12 by side 11b near
side 11a. Detector 16a is mounted at a position on frame 12 by side
11d near side 11c. Each of detectors 14a and 16a comprises an
infrared sensor that can detect infrared rays radiated from all
regions. Alternatively, detectors 14a and 16a may comprise distance
sensors.
[0107] Control circuit 22 controls the direction of an image
displayed on display screen 11 based on a detection signal
generated from detector 14a and a detection signal generated from
detector 16a.
[0108] For example, control circuit 22 determines that the user
exists a position in close to side 11a or 11b when the detection
signal (output voltage), which is generated from detector 14a, is
larger than the detection signal (output voltage), which is
generated from detector 16a. Subsequently, control circuit 22
detects the difference between the detection signal (output
voltage) generated from detector 14a and the detection signal
(output voltage) generated from detector 16a. When the difference
exceeds a previously set predetermined value, control circuit 22
determines that the user exists near side 11b. On the other hand,
when the difference does not exceed the previously set
predetermined value, control circuit 22 determines that the user
exists near side 11a.
[0109] Control circuit 22 determines that the user exists a
position near side 11c or 11d when the detection signal (output
voltage), which is generated from detector 14a, is smaller than the
detection signal (output voltage), which is generated from detector
16a. Subsequently, control circuit 22 detects the difference
between the detection signal (output voltage) generated from
detector 14a and the detection signal (output voltage) generated
from detector 16a. Controller 22 determines that the user exists
near side 11d when the difference exceeds a previously set
predetermined value. On the other hands, when the difference does
not exceed the previously set predetermined value, control circuit
22 determines that the user exists near side 11c. Control circuit
22 sets the direction of an image such that the bottom of the image
is moved to the side near which the user exists.
[0110] In the example illustrated in FIG. 5, the configuration can
be simplified because a less number of detectors are required than
the embodiment illustrated in FIG. 2.
[0111] The positions of detectors 14a and 16a mounted on frame 12
are not limited to the foregoing ones. The positions of detectors
14a and 16a mounted on frame 12 can be changed as appropriate as
long as respective detectors 14a and 16b generate different output
voltages when the user exists near side 11a, 11b, 11c, or 11d.
[0112] While preferred embodiments of the present invention have
been described using specific terms, such description is for
illustrative purposes only, and it is to be understood that changes
and variations may be made without departing from the spirit or
scope of the following claims.
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